Onsen suppon geisha was part of a Hot Springs series, with Sugimoto having debuted in the first installment in 1971. In this one, she’s so good at using that super strong vagina of hers that she can fuck guys to death. In the end, she’s pitted against a sexual superman and a showdown ensues. There’s also a subplot about a mad scientist type who needs vaginal juices to create a potion designed to turn Japanese girls black.